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Systems based on multiswitches are professional and popular solutions for distributing terrestrial FM and TV broadcasts (FM/DAB(+) and DVB-T) and satellite signals (DVB-S/S2) to multiple subscriber outlets. The end users can decide about the programming buying suitable televisions, satellite receivers, signing individual contracts with satellite operators.
TERRA products dedicated for shared antenna systems are first-class equipment with a four-year warranty. SMATV distribution networks based on these devices ensure reliable operation for a long time. The distinguish features of TERRA multiswitch systems include:
- large scalability - solutions even for 1000 or so outlets
- die cast housings ensuring high screening efficiency and resistance to interferences
- high isolation between inputs and between outputs – multiswitches of lower categories with insufficient isolation are the most common source of problems in SMATV systems
- switches instead of potentiometers ensure stable adjustment of gain / signal level and cable attenuation compensation - increased temperature and long-term stability of these parameters
- cable attenuation compensation and groups of outputs with different signal levels allow for equalization of signal levels throughout the whole network, independently from different lengths of the cables
- multi-path splitters save place in installation boxes
- supplying of multiswitches from satellite receivers of the users - lower energy consumption
- several powering options for amplifiers – e.g. one 230 VAC power point can be sufficient for a system with hundreds of outlets
- free software for designers - SatNet
- free design examples in pdf/dwg files for AutoCad users
Star topology systems - radial multiswitches with power supplies - MR series
The multiswitches are designed for the simplest networks, mainly up to 32 outlets. Such installations based on single MR or SIGNAL multiswitches usually do not need special designs, unless they include long distribution paths. In this case, it is necessary to determine signal levels in all outlets and verify if they are compliant with standards. The multiswitches are also suitable for designing radial networks which consist of more than one device. In such installations, the signal is distributed to the radial multiswitches with required number of outputs from the main path through splitters and taps. When the total number of active devices does not exceed a dozen, only one of the multiswitches has to be connected to 230 VAC power network.
 5/8 Multiswitch Terra MR-508 (active terrestrial path) |  5/12 Multiswitch Terra MR-512 (active terrestrial path) |
 5/16 Multiswitch Terra MR-516 (active terrestrial path) |  5/24 Multiswitch Terra MR-524 (active terrestrial path) |  5/32 Multiswitch Terra MR-532 (active terrestrial path) |
An important advantage of MR-5XX multiswitches is diversification of signal levels at different groups of outputs. It allows to compensate the differences in attenuation of various lengths of cables that have to be used in the installation - we can get similar levels in all outlets. Additionally, the multiswitches compensate cable characteristics (provide higher levels for higher frequencies).
MR-5XX radial multiswitches properly distribute satellite DVB-S/S2 signals and terrestrial DVB-T broadcasts
Bus topology systems - MV series
The implementation of bus topology with the use of MV-5XX multiswitches can provide the most flexible solutions for SMATV systems. It is easy to create subnetworks determined by the physical layout of outlets in large, multi-story and multi-staircase buildings. With increasing demands of the users (e.g. for additional signal for twin-tuner PVR receivers), it will be sufficient to change the multiswitch in the subnetwork to a model with a larger number of outputs.
Bus topology offers a number of advantages over cascade solutions. The most important of these is the minimization of the impact of a failure in one network segment on the rest of the system. In the solution proposed by TERRA company, a failure of a multiswitch causes a loss of signal only in the outlets connected to the multiswitch, the rest of the network is unaffected. Another solution, unique on the European scale, is a centralized power supply method. The TERRA SA-51 R70501 amplifier can power LNB and up to 25 multiswitches, which in practice translates into the possibility of building a multiswitch system with hundreds of outlets, powered only from one AC power outlet.
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The multiswitches of MV-5XX series are dedicated mainly for applications in large, multi-staircase multi-story buildings. The high maximum output level and compensation of the attenuation caused by coaxial cables, plus outputs with graded signal levels - allow for building large systems with cable runs up to 80 meters (between outputs and subscriber outlets).
Broadband amplifiers of SA series
The amplifiers have been equipped with independent gain adjustments in all satellite paths (gain up to 22 dB) and in terrestrial path (gain up to 22 dB). Additional "Slope" switches allow for compensation of the attenuation of coaxial cables. The maximum output levels are 114 dBµV (IMD3) for satellite paths and 109 dBµV for terrestrial TV path.
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Due to the innovative way of centralized power supply implemented by Terra company, the important parameter of the amplifiers, which also provide power to the rest of the systems, is the current capacity. Via their H lines, the SA amplifiers can provide up to 2 A (one MV multiswitch takes about 80 mA).
Passive system components - splitters and taps of SD-5XX series
Splitters and taps of SD-5XX series are used in multiswitch systems for sub-network partition.
Each of the taps is equipped with DC-transition switch that in "ON" position runs current through "H" paths to both branches. In "OFF" position it is possible only within one path.
It is worth mentioning the difference between splitters and taps - in addition to different levels of attenuation, taps feature much higher compensation of cable attenuation.
It is worth mentioning the difference between splitters and taps - in addition to different levels of attenuation, taps feature much higher compensation of cable attenuation.
Examples of multiswitch systems (for one satellite) based on bus topology
In the case of multi-story buildings, the choice of bus topology is usually the best solution. This topology allows for easy distribution of signals to outlets located on individual floors, and using passive components and subnetworks - in individual staicases (risers).
A SMATV system in a multi-family building with 36 outlets. The system is based on Terra MV 5XX multiswitches, SD-504 R70515 splitter, and SD-515 R70517 tap. The whole system is powered from the PS182F R71465 power supply (18 V, 2A). The first stage of the system is the SA-511 R70511 broadband amplifier.
